* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        /* Framework handles body styling */

        /* Framework handles container styling */

        /* Framework handles header styling */

        .mode-selector {
            display: flex;
            gap: 10px;
            margin-bottom: 30px;
            flex-wrap: wrap;
        }

        .mode-btn {
            padding: 12px 24px;
            border: none;
            border-radius: 25px;
            background: #f0f0f0;
            color: #333;
            cursor: pointer;
            transition: all 0.3s ease;
            font-size: 14px;
        }

        .mode-btn.active {
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
        }

        .mode-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 5px 15px rgba(0,0,0,0.2);
        }

        .calculator-section {
            display: none;
        }

        .calculator-section.active {
            display: block;
        }

        .input-group {
            margin-bottom: 20px;
        }

        .input-group label {
            display: block;
            margin-bottom: 8px;
            font-weight: 600;
            color: #333;
        }

        .input-group input, .input-group select {
            width: 100%;
            padding: 12px;
            border: 2px solid #e0e0e0;
            border-radius: 10px;
            font-size: 16px;
            transition: border-color 0.3s ease;
        }

        .input-group input:focus, .input-group select:focus {
            outline: none;
            border-color: #667eea;
        }

        .calculate-btn {
            width: 100%;
            padding: 15px;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            border: none;
            border-radius: 10px;
            font-size: 18px;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
            margin-bottom: 20px;
        }

        .calculate-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 10px 20px rgba(0,0,0,0.2);
        }

        .result {
            background: #f8f9fa;
            padding: 20px;
            border-radius: 10px;
            border-left: 4px solid #667eea;
            margin-top: 20px;
        }

        .result h3 {
            color: #333;
            margin-bottom: 15px;
        }

        .result-item {
            display: flex;
            justify-content: space-between;
            margin-bottom: 10px;
            padding: 8px 0;
            border-bottom: 1px solid #e0e0e0;
        }

        .result-item:last-child {
            border-bottom: none;
        }

        .result-label {
            font-weight: 600;
            color: #555;
        }

        .result-value {
            font-weight: 700;
            color: #667eea;
        }

        .distribution-chart {
            background: white;
            border: 1px solid #e0e0e0;
            border-radius: 10px;
            padding: 20px;
            margin-top: 20px;
            text-align: center;
        }

        .chart-container {
            width: 100%;
            height: 300px;
            position: relative;
            margin: 20px 0;
        }

        .normal-curve {
            width: 100%;
            height: 100%;
            position: relative;
        }

        .z-score-marker {
            position: absolute;
            top: 50%;
            transform: translateY(-50%);
            width: 2px;
            height: 20px;
            background: #e74c3c;
            border-radius: 1px;
        }

        .z-score-label {
            position: absolute;
            top: 60%;
            transform: translateX(-50%);
            background: #e74c3c;
            color: white;
            padding: 2px 6px;
            border-radius: 4px;
            font-size: 12px;
            font-weight: 600;
        }

        .info-box {
            background: #e3f2fd;
            border: 1px solid #2196f3;
            border-radius: 10px;
            padding: 15px;
            margin-bottom: 20px;
        }

        .info-box h4 {
            color: #1976d2;
            margin-bottom: 10px;
        }

        .info-box p {
            color: #424242;
            line-height: 1.6;
        }

        .formula-box {
            background: #fff3e0;
            border: 1px solid #ff9800;
            border-radius: 10px;
            padding: 15px;
            margin-bottom: 20px;
        }

        .formula-box h4 {
            color: #f57c00;
            margin-bottom: 10px;
        }

        .formula {
            font-family: 'Courier New', monospace;
            background: #f5f5f5;
            padding: 10px;
            border-radius: 5px;
            margin: 10px 0;
            text-align: center;
            font-size: 16px;
        }

        .back-link {
            display: inline-block;
            margin-top: 20px;
            color: #667eea;
            text-decoration: none;
            font-weight: 600;
            transition: color 0.3s ease;
        }

        .back-link:hover {
            color: #764ba2;
        }

        .cross-links {
            background: #f8f9fa;
            border-radius: 10px;
            padding: 20px;
            margin-top: 30px;
        }

        .cross-links h3 {
            color: #333;
            margin-bottom: 15px;
        }

        .cross-links-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 10px;
        }

        .cross-links a {
            color: #667eea;
            text-decoration: none;
            padding: 8px 12px;
            border-radius: 5px;
            transition: background-color 0.3s ease;
        }

        .cross-links a:hover {
            background: #e3f2fd;
        }

        @media (max-width: 768px) {
            .header h1 {
                font-size: 2em;
            }
            
            .mode-selector {
                flex-direction: column;
            }
            
            .mode-btn {
                text-align: center;
            }
            
            .result-item {
                flex-direction: column;
                gap: 5px;
            }
            
            .cross-links-grid {
                grid-template-columns: 1fr;
            }
        }